The invention relates to a method for producing panels, in particular flooring panels, comprising an upper usable surface and locking profiles for mechanical locking of similar panels to one another, wherein recesses are provided on at least two edge regions of the usable surface lying opposite one another and wherein the recesses of two similar panels locked to one another form a mutual join. The invention further relates to a half-form for producing panels, in particular flooring panels, in particular according to the stated method, with at least two grooves running substantially parallel and separated from one another by at least one web. The invention also relates to a pressing tool for pressing a carrier plate with at least one wear layer, in particular for producing a half-form of the stated type, wherein the pressing tool comprises at least two raised rib structures running substantially parallel to one another for imprinting at least two substantially parallel grooves in a half-form.
Flooring panels or panels put to other uses are typically provided with decoration. This makes the panels attractive and allows them to be used for various purposes. Here it has been increasingly sought to improve the visual and haptic impression of the panels. The decoration of, by way of example, flooring panels is often inspired by the appearance of, by way of example, solid wood, tiles or stones, so that in the laid state of the flooring panels the impression of a wooden floor, tiled floor, stone floor or similar is created. In order to imitate the original as closely as possible, the usable surface of the panels can, by way of example, be intentionally provided with recesses or elevations, so that surface textures are obtained which correspond to those of wood, tiles, stones and similar. An example of this is what are known as wood pores, which can be imitated by selective recesses in the usable surface of the panels.
Here, the usable surface is considered to be the surface of the panels, which contributes to forming the upper surface of the layer formed by a plurality of panels joined together. The usable surface typically has four edges, beyond which optionally locking profiles of the panels can extend further outwards which serve only to join the panels and not to form the upper surface of a layer made up of panels. Here, the locking profiles are preferably configured so that they allow a mechanical, in particular positive-fit, locking of the panels against one another. Here the locking expediently works both in a direction parallel to the panel plane and vertically to the corresponding side edge, and vertically to the panel plane.
It is often desirable to imitate a join between panels joined together, as happens with wall, ceiling or floor coverings of wooden floorboards, stones or tiles. This is achieved by the edge regions of the useful surfaces of the panels being chamfered or rounded. When similar panels are in the joined state, the recesses form a mutual join, which by way of example can have a V-shaped cross-section, for instance in order to imitate the joins between floorboards. By adjusting the cross-section of the joins formed by two adjacent panels or the form of the recesses in the edge regions of the useful surfaces other coverings can also be imitated.
The production of panels having such recesses is very complicated, however, or results in a large proportion of defective panels. Typically, to begin with half-forms in the form of sheets are produced, which may have a multi-layered structure. Here, this multi-layer structure can already correspond to that of the panels to be produced. The half-forms usually have a carrier plate in a wooden material, for instance a fibreboard, on which an upper decorative wear layer and a lower backing layer are arranged. Optionally, impact sound insulation can also be added as a finish below. The wear layer and the backing layer have in particular at least a paper impregnated with resin, for instance melamine resin. Further such layers can be provided. In addition, particles to increase the wear resistance can also be used by way of example. In addition, the wear layer and the backing layer are typically pressed with the carrier plate. The wear layer and the backing layer can, however, also be formed by the application of at least one varnish layer in each case. In this case, the decoration of the wear layer is preferably printed onto the half-form.
Here, in the side of the half-form forming the usable surface, grooves, in particular with chamfered or rounded usable surfaces can be pressed, which at least partially form the recesses in the edge regions of the useful surfaces of the subsequent panels. From the half-form, in a downstream processing step, panel blanks are then cut out along the grooves, wherein the groove is partly removed. At the latest at the time of the machining of the locking profiles the groove has been removed to such an extent that on the finished panel only the recesses in the edge regions of the useful surfaces remain.
Both when separating the half-form into half-form parts, in particular panel blanks, and when machining the locking profiles, inaccuracies may arise. Thus, sometimes more and sometimes less of the groove pressed into the half-form is removed, for which reason the recesses in the edge regions of the usable surface may differ from panel to panel. This can, by way of example, result in the joins not being straight or being of different widths between the panels joined together. If the recesses of panels joined together do not meet each other in the panel joining area, moisture may penetrate the carrier plate in the vicinity of the mismatch, in particular if the carrier plate is made from a wooden material. In order to prevent these disadvantages, more technical equipment has to be used and the speed of production considerably reduced in order to be able to increase the production accuracy. The production is then associated with significantly higher costs, however.